Avoid the 1-based indexing on the WalHashLoc.aPgno[] array. Make it 0-indexed

instead.

FossilOrigin-Name: 28f5f709b4b28ba7f6f56bdd4a9e8c04d0d2df90d13d6df1a589fa4a65163f4d
This commit is contained in:
drh 2021-10-27 20:23:59 +00:00
parent 5f25627a1c
commit 71c3ea7523
3 changed files with 27 additions and 31 deletions

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@ -1,5 +1,5 @@
C Improve\sthe\scomment\son\swalIndexPage()\sto\smore\saccurately\sdescribe\sthe\npost-conditions.
D 2021-10-27T19:57:59.451
C Avoid\sthe\s1-based\sindexing\son\sthe\sWalHashLoc.aPgno[]\sarray.\s\sMake\sit\s0-indexed\ninstead.
D 2021-10-27T20:23:59.854
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@ -633,7 +633,7 @@ F src/vdbetrace.c fe0bc29ebd4e02c8bc5c1945f1d2e6be5927ec12c06d89b03ef2a4def34bf8
F src/vdbevtab.c f99b275366c5fc5e2d99f734729880994ab9500bdafde7fae3b02d562b9d323c
F src/vtab.c d07cc24dd84b0b51bf05adb187b0d2e6b0cac56cfbc0197995a26d4f8fa5c7e2
F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
F src/wal.c 2bf6d846140a3ef6ac4dae85e993e98dd304e03641ccef65904744eb85e65e2e
F src/wal.c 2fd68f0a2e12486a543016ee47828874863c486b8a090989e70627f556ccde32
F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
F src/where.c ecabef93b0f14442a73eca205fc960428984d75fbdc7d60226b7fc9cac127187
@ -1929,10 +1929,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
P 7238d58051bfdcea8f7a4aeab89145849d0659c987df9063aacafe97be6657fe
R d7b0bf6adaa4481b0cdf4adead947bd2
T *branch * wal-tuneup
T *sym-wal-tuneup *
T -sym-trunk *
P b619e936455f4001b543a9a58dea2ac9ebd598327d6be01130ca6e7e9764ffe6
R 0450e5bea2ea312618d6c5cbc7e1928c
U drh
Z 903a3bc4a6ff5101d13b9fbd42b22ae8
Z 2a7a0238c8886bf3fdd3adf1dc184586

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@ -1 +1 @@
b619e936455f4001b543a9a58dea2ac9ebd598327d6be01130ca6e7e9764ffe6
28f5f709b4b28ba7f6f56bdd4a9e8c04d0d2df90d13d6df1a589fa4a65163f4d

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@ -1000,8 +1000,8 @@ struct WalHashLoc {
** slot in the hash table is set to N, it refers to frame number
** (pLoc->iZero+N) in the log.
**
** Finally, set pLoc->aPgno so that pLoc->aPgno[1] is the page number of the
** first frame indexed by the hash table, frame (pLoc->iZero+1).
** Finally, set pLoc->aPgno so that pLoc->aPgno[0] is the page number of the
** first frame indexed by the hash table, frame (pLoc->iZero).
*/
static int walHashGet(
Wal *pWal, /* WAL handle */
@ -1021,7 +1021,6 @@ static int walHashGet(
}else{
pLoc->iZero = HASHTABLE_NPAGE_ONE + (iHash-1)*HASHTABLE_NPAGE;
}
pLoc->aPgno = &pLoc->aPgno[-1];
}
return rc;
}
@ -1103,8 +1102,9 @@ static void walCleanupHash(Wal *pWal){
/* Zero the entries in the aPgno array that correspond to frames with
** frame numbers greater than pWal->hdr.mxFrame.
*/
nByte = (int)((char *)sLoc.aHash - (char *)&sLoc.aPgno[iLimit+1]);
memset((void *)&sLoc.aPgno[iLimit+1], 0, nByte);
nByte = (int)((char *)sLoc.aHash - (char *)&sLoc.aPgno[iLimit]);
assert( nByte>=0 );
memset((void *)&sLoc.aPgno[iLimit], 0, nByte);
#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
/* Verify that the every entry in the mapping region is still reachable
@ -1113,11 +1113,11 @@ static void walCleanupHash(Wal *pWal){
if( iLimit ){
int j; /* Loop counter */
int iKey; /* Hash key */
for(j=1; j<=iLimit; j++){
for(j=0; j<iLimit; j++){
for(iKey=walHash(sLoc.aPgno[j]);sLoc.aHash[iKey];iKey=walNextHash(iKey)){
if( sLoc.aHash[iKey]==j ) break;
if( sLoc.aHash[iKey]==j+1 ) break;
}
assert( sLoc.aHash[iKey]==j );
assert( sLoc.aHash[iKey]==j+1 );
}
}
#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
@ -1149,9 +1149,9 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
** entire hash table and aPgno[] array before proceeding.
*/
if( idx==1 ){
int nByte = (int)((u8 *)&sLoc.aHash[HASHTABLE_NSLOT]
- (u8 *)&sLoc.aPgno[1]);
memset((void*)&sLoc.aPgno[1], 0, nByte);
int nByte = (int)((u8*)&sLoc.aHash[HASHTABLE_NSLOT] - (u8*)sLoc.aPgno);
assert( nByte>=0 );
memset((void*)sLoc.aPgno, 0, nByte);
}
/* If the entry in aPgno[] is already set, then the previous writer
@ -1160,9 +1160,9 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
** Remove the remnants of that writers uncommitted transaction from
** the hash-table before writing any new entries.
*/
if( sLoc.aPgno[idx] ){
if( sLoc.aPgno[idx-1] ){
walCleanupHash(pWal);
assert( !sLoc.aPgno[idx] );
assert( !sLoc.aPgno[idx-1] );
}
/* Write the aPgno[] array entry and the hash-table slot. */
@ -1170,7 +1170,7 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
for(iKey=walHash(iPage); sLoc.aHash[iKey]; iKey=walNextHash(iKey)){
if( (nCollide--)==0 ) return SQLITE_CORRUPT_BKPT;
}
sLoc.aPgno[idx] = iPage;
sLoc.aPgno[idx-1] = iPage;
AtomicStore(&sLoc.aHash[iKey], (ht_slot)idx);
#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
@ -1191,19 +1191,18 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
*/
if( (idx&0x3ff)==0 ){
int i; /* Loop counter */
for(i=1; i<=idx; i++){
for(i=0; i<idx; i++){
for(iKey=walHash(sLoc.aPgno[i]);
sLoc.aHash[iKey];
iKey=walNextHash(iKey)){
if( sLoc.aHash[iKey]==i ) break;
if( sLoc.aHash[iKey]==i+1 ) break;
}
assert( sLoc.aHash[iKey]==i );
assert( sLoc.aHash[iKey]==i+1 );
}
}
#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
}
return rc;
}
@ -1821,7 +1820,6 @@ static int walIteratorInit(Wal *pWal, u32 nBackfill, WalIterator **pp){
int nEntry; /* Number of entries in this segment */
ht_slot *aIndex; /* Sorted index for this segment */
sLoc.aPgno++;
if( (i+1)==nSegment ){
nEntry = (int)(iLast - sLoc.iZero);
}else{
@ -2960,7 +2958,8 @@ int sqlite3WalSnapshotRecover(Wal *pWal){
rc = walHashGet(pWal, walFramePage(i), &sLoc);
if( rc!=SQLITE_OK ) break;
pgno = sLoc.aPgno[i-sLoc.iZero];
assert( i - sLoc.iZero - 1 >=0 );
pgno = sLoc.aPgno[i-sLoc.iZero-1];
iDbOff = (i64)(pgno-1) * szPage;
if( iDbOff+szPage<=szDb ){
@ -3193,7 +3192,7 @@ int sqlite3WalFindFrame(
iKey = walHash(pgno);
while( (iH = AtomicLoad(&sLoc.aHash[iKey]))!=0 ){
u32 iFrame = iH + sLoc.iZero;
if( iFrame<=iLast && iFrame>=pWal->minFrame && sLoc.aPgno[iH]==pgno ){
if( iFrame<=iLast && iFrame>=pWal->minFrame && sLoc.aPgno[iH-1]==pgno ){
assert( iFrame>iRead || CORRUPT_DB );
iRead = iFrame;
}